1. Field of the Invention
The present invention relates to an objective lens device, and more particularly to an objective lens device for a microscope that has a telescopic tube assembly with an objective lens and adjusts the magnification and focal length by retracting or extending the telescopic tube assembly.
2. Description of Related Art
Microscopes are used generally for observation microbes, cells or specific material microstructure.
A conventional microscope has a base, an arm, a head, an eyepiece, a turret, multiple object lenses and a stage. The arm is mounted on the base and has a distal end. The head is mounted on the distal end of the arm. The eyepiece is mounted to the head. The turret is mounted rotatably to the head. The multiple objective lenses are mounted to the turret and have different powers. One of the objective lenses can be aligned with the eyepiece by rotating the turret to make the microscope has a specific magnification. The stage is mounted slidably to the arm, is aligned with a corresponding objective lens and has a retainer to hold a target such as glass slides with cells or specific material.
However, each objective lens has an unmodifiable focal length and a specific power that can not be adjusted to change the magnification of the microscope without replacing the objective lens. The microscope with the multiple objective lenses makes its cost high.
Moreover, moving the stage with the target up or down is necessary to precisely match the focal length of the objective lens, besides turning the turret for alignment of the objective lenses. The adjustments of the turret and the stage are inconvenient and inefficient.
To overcome the shortcomings, the present invention provides an objective lens device for a microscope to mitigate or obviate the aforementioned problems.